Odin Works O2 Lite Forend, 15.5, Black, M-LOK, Fits AR-15 F-15-ML-O2 The O2 Lite is the latest and lightest of all the ODIN Works forends. Precision machined from 6005-T651" the O2 lite is a full 20% lighter than its predecessors. All ODIN Works forends are free floating for accuracy and hard anodized for durability.